Conventionally, there is known a method of performing, in performing an interpolation process for an image using a bi-cubic method, adjustment of an interpolation coefficient near an edge of the image and a change of a sampling interval and sequentially performing interpolation in the horizontal direction and the vertical direction (see, for example, Patent Document 1). Patent Document 1: Japanese Patent Application Laid-Open No. 2006-54899 (pages 8 to 19, FIGS. 1 to 15).